1. Field of the Invention
The present invention relates to a 3D image reconstructing apparatus and a 3D object information inputting apparatus and, more particularly to a 3D image reconstructing apparatus for reconstructing a 3D still or moving image and permitting an observer to observe the 3D image in a natural state and without strain on an observer""s eyes and a 3D objective information inputting apparatus that can pick up and record an image of a 3D object readily.
2. Related Background Art
Various methods have been attempted heretofore as methods for three-dimensionally reconstructing a 3D object. Among them, methods for achieving an observer""s stereoscopic vision using binocular parallax (a polarizing spectacle method, a lenticular method, etc.) are popularly used; however, since there occurs contradiction between three-dimensional recognition by the accommodation function of eye and stereoscopic recognition by the binocular parallax, the observer often feels tired or incompatible. There are thus many attempts to find methods for reconstruction of 3D images to satisfy the other three-dimensional recognition functions of the eye without relying on only the binocular parallax.
Such 3D image reconstructing methods include, for example, the following two prior art methods, which will be described with problems of the respective methods.
The first prior art method is a method of IP (Integral Photo) system utilizing pinholes, as proposed in Japanese Laid-open Patent Application No. 6-133340 and as shown in FIG. 1. FIG. 1 is a schematic view to show the major part of the xe2x80x9cstereoscopic image reconstructing apparatusxe2x80x9d used in this method. This apparatus is composed of a pinhole panel 114 and a multi-image surface 112. In the pinhole panel 114 pinholes 113 are disposed horizontally and vertically at small intervals and in parallel, and the other portions have a light intercepting property. When an object 116 is present in front of the pinhole panel 114, small images 111 are formed by rays passing the respective pinholes on the multi-image surface 112.
When these small images all are recorded as multi-photos 115 and again placed on the multi-image surface, such rays as to reversely trace the rays emitted from the object 116 upon recording go out through each pinhole 113, thereby reconstructing a stereoscopic image similar to the object 116. However, since the rays are sampled only at positions of the pinholes both upon recording and upon reconstruction, all the rays emitted from the actual object cannot be reconstructed.
Then the method described in Japanese Laid-open Patent Application No. 6-160770 uses an electronic display panel capable of displaying a dynamic image for each of the pinhole panel 114 and the multi-image surface 112; the pinhole position is moved at high speed in time division and a group of small images according to pinhole positions at respective times are displayed at high speed on the multi-image surface 112, thereby preventing decrease in the number of rays upon reconstruction. The observer can observe a stereoscopic image with improved luminance and as if the rays radiate from the entire surface of the pinhole panel 114, thanks to the afterimage effect of the eye. Dynamic stereoscopic images can also be reconstructed by use of the electronic display panel.
Meanwhile, the 3D object information input apparatus dedicated to this 3D image reconstructing apparatus can be constructed by placing an image pickup element instead of the display panel on the multi-image surface 112 in the same structure.
The stereoscopic image reconstructing apparatus shown in FIG. 1 permits many people to observe a stereoscopic image simultaneously without any special device such as spectacles and also permits an observer to observe a stereoscopic image from different observing points.
However, the stereoscopic image reconstructing apparatus shown in FIG. 1 has the following problems.
First, since the diameter of the pinholes cannot be set below a certain value in view of the luminance of reconstructed image, it is unavoidable for the rays after passage through the pinholes to have some considerable spread. This causes decrease in the resolution of the reconstructed image.
Second, the observer""s eyes must be focused on the image surface, which makes a contradiction against recognition by binocular parallax and which exerts a great stress on the observer""s eyes.
Third, since the resolution of the small images recorded on the multi-image surface is reflected to that of the reconstructed stereoscopic image as it is, a display panel with a very high resolution needs to be used in order to achieve a stereoscopic image in a sufficient resolution.
Further, the second prior art method is a method for reconstructing a 3D object by use of the holography technology, for example, as proposed in Japanese Laid-open Patent Application No. 64-84993. FIG. 2 is a schematic view of a real-time hologram reconstructing apparatus using a liquid-crystal dot matrix display device used in this method.
In the drawing, a microprocessor 25-1 and a video control apparatus 25-2 produce interference fringe patterns to enable reconstruction of a desired three-dimensional image and a driver circuit 25-3 writes the above interference fringe patterns as bright and dark patterns on a liquid-crystal dot matrix device 25-4.
The patterns are irradiated by laser light emitted from a laser emitting circuit 25-5 and observed along direction A, whereby the observer can observe a three-dimensional image displayed on the liquid-crystal dot matrix device 25-4. Further, the apparatus permits the observer to observe a three-dimensional dynamic image, by dynamically changing the interference fringe patterns written on the liquid-crystal dot matrix device 25-4.
However, the real-time hologram reconstructing apparatus as a 3D image reconstructing apparatus shown in FIG. 2 has the following problems.
First, the resolution of the liquid-crystal dot matrix device as a space modulator for displaying the interference fringe patterns is considerably lower than that of photosensitive materials such as the conventional film, so that angles of diffraction of reconstructing light cannot be made so large. Therefore, the observation area of reconstructed image becomes narrow.
Second, the effective area of the space modulator capable of forming such fine interference fringe patterns, as used in the real-time hologram reconstructing apparatus, cannot be made so large in general. Therefore, the size of reconstructed image is limited.
Third, utilization efficiency of diffracted light of the space modulator capable of forming such fine interference fringe patterns, as used in the real-time hologram reconstructing apparatus, is generally very low.
Fourth, information amounts of the interference fringe patterns displayed on the space modulator are too large to be processed by the arithmetic and process system of the interference fringe patterns.
According to the first aspect of the present invention, an object is to provide a 3D image reconstructing apparatus that permits the observer to observe a 3D image in a natural state and without strain and a 3D object information input apparatus that can perform input and record of 3D object information from an existing object by a simple structure, and the apparatus for solving the problems of the first prior art described above is constructed as follows.
A 3D image reconstructing apparatus is a three-dimensional image reconstructing apparatus for reconstructing a three-dimensional image and permitting the three-dimensional image to be observed at an observation position by use of image display means for displaying image information, spatial light modulating means for forming a fine aperture, an optical system disposed near the spatial light modulating means, and control means for controlling the image display means and the spatial light modulating means so that some rays outgoing through the fine aperture of the spatial light modulating means and the optical system out of rays from the image information displayed on the image display means pass a predetermined point in a three-dimensional space within a fixed period, wherein a distance between two closest rays passing the predetermined point and reaching the observation position is determined based on a diameter of a pupil of an observer (this configuration will be referred to as configuration A).
Particularly, the apparatus is characterized by the following configurations.
The distance between the two closest rays reaching the observation position is determined to be not more than the diameter of the pupil of the observer.
The distance between the two closest rays reaching the observation position is determined to be not more than 2 mm.
A configuration of the spatial light modulating means is determined so that a maximum diameter of rays outgoing through the fine aperture of the spatial light modulating means and the optical system becomes not more than the diameter of the pupil of the observer.
A configuration of the spatial light modulating means is determined so that a maximum diameter of rays outgoing through the fine aperture of the spatial light modulating means and the optical system becomes not more than 2 mm.
The control means controls the spatial light modulating means so that only a vertical length of the fine aperture of the spatial light modulating means becomes equal to a vertical length of an entire area of the spatial light modulating means.
The control means controls the fine aperture of the spatial light modulating means so as to move the fine aperture throughout an entire area of the spatial light modulating means without duplication within the fixed period.
The fixed period is shorter than a permissible time of afterimage of the observer.
The fixed period is within a range of {fraction (1/30)} to {fraction (1/60)} sec.
The image information is equal to image information obtained when the three-dimensional image to be reconstructed is reversely projected onto an image display surface of the image display means through the spatial light modulating means and the optical system.
Each of the spatial light modulating means, the optical system, and the image display means is divided into plural areas, the optical system is arranged so that the divisional areas have respective optical axes different from each other, the spatial light modulating means is arranged so that a single fine aperture is formed in every area, and the image display means is arranged so that image information is displayed in every area.
A light-intercepting partition is provided in a space between the image display means and the optical system so that light forming the image information displayed in each of the plural divisional areas of the image display means is incident to only a corresponding area of the optical system.
The controlling means controls an existing area of the fine aperture of the spatial light modulating means and the image information, so that directivity is given to a predetermined point in the 3D space veiwed from the observation position.
The control means performs a hidden-surface process of the reconstructed image by such a control that when one ray outgoing through the fine aperture of the spatial light modulating means and the optical system passes plural points on the reconstructed image in the three-dimensional space, the predetermined point in the three-dimensional space becomes a farthest point from the fine aperture.
A refracting member is provided on the light incidence side or on the light emergence side of the spatial light modulating means.
The control means comprises reversing means for reversing the image information.
The spatial light modulating means is comprised of a transmission type liquid-crystal display device.
The spatial light modulating means is located closer to the observer than the image display means.
A 3D object information input apparatus of the present invention is a three-dimensional object information input apparatus wherein the image display means of the three-dimensional image reconstructing apparatus of configuration A is replaced by image pickup means, the three-dimensional object information input apparatus being arranged to achieve time-series input of image information projected onto the image pickup means and position information of the fine aperture at that time while controlling the position of the fine aperture of the spatial light modulating means in the same manner as in the three-dimensional image reconstructing apparatus.
Particularly, the apparatus is characterized by the following configuration.
The image pickup means comprises image reversing means.
According to the second aspect of the present invention, an object is to provide a 3D image reconstructing apparatus that can accurately and quickly reconstruct a large predetermined 3D image in a wide observation area in a 3D space and that permits the observer to observe a good 3D image, and the apparatus for solving the problems of the second prior art described previously is constructed as follows.
A 3D image reconstructing apparatus of the present invention is a three-dimensional image reconstructing apparatus having a light source array in which a plurality of light source portions for radiating rays with single directivity are arrayed, ray emission direction control means for emitting the rays therefrom while controlling the rays from the plural light source portions of the light source array independently of each other, and control means for controlling radiating states of the plural light source portions and ray emission directions from the ray emission direction control means so that a set of rays from the ray emission direction control means pass a predetermined point in a three-dimensional space within a fixed unit period, wherein when a three-dimensional image of the predetermined point is reconstructed and the three-dimensional image of the predetermined point is observed at an observation position, utilizing these means, the control means controls a distance between two closest rays passing the predetermined point and reaching the observation position in accordance with a diameter of a pupil of an observer (this configuration will be referred to as configuration B).
Particularly, the apparatus is characterized by the following configurations.
The control means controls the distance between the two closest rays reaching the observation position so as to be not more than the diameter of the pupil of the observer.
The control means keeps the distance between the two closest rays reaching the observation position, not more than 2 mm.
The fixed unit period is shorter than a permissible time of afterimage of the observer.
The fixed unit period is within a range of {fraction (1/30)} to {fraction (1/60)} sec.
The ray emission direction control means has a vibratory microlens array.
Emission directions of rays omitted from the ray emission direction control means are controlled by relative vibration between the light source array and the ray emission direction control means.
The relative vibration between the light source array and the ray emission direction control means is a zigzag motion.
The light source portion has a radiating portion and a collimator lens for condensing rays from the radiating portion and for emitting the rays in the form of parallel light.
A telecentric system for making principal rays from the plural light source portions of the light source array outgoing in the form of nearly parallel light is provided on the light emission side of the light source array.
The microlens array has a thickwise cross section comprised of a continuous wave shape.
Rays from the predetermined point when observed from the observation position are provided with directivity by controlling radiating states of light source portions within a predetermined area out of the plural light source portions of the light source array.
The control means performs a hidden-surface process of the reconstructed image so that when one ray from the light source portion passes plural points on the reconstructed image in the three-dimensional space, the predetermined point in the three-dimensional space when observed from the observation position becomes a farthest point from the ray emission direction control means among the plural points.
A refracting member is provided on the light incidence side or on the light emergence side of the ray emission direction control means.
Another 3D image reconstructing apparatus of the present invention is a three-dimensional image reconstructing apparatus having a light source array in which a plurality of light source portions for radiating rays with single directivity are arrayed, ray emission direction control means for emitting the rays therefrom while controlling the rays from the plural light source portions of the light source array independently of each other, and control means for controlling radiating states of the plural light source portions and ray emission directions from the ray emission direction control means so that a set of rays from the ray emission direction control means pass a predetermined point in a three-dimensional space within a fixed unit period, wherein when a three-dimensional image of the predetermined point is reconstructed and the three-dimensional image of the predetermined point is observed at an observation position, utilizing these means, the control means determines a distance between two closest rays passing the predetermined point and reaching the observation position, based on a diameter of a pupil of an observer.
Particularly, the apparatus is characterized by the following configurations.
The control means determines the distance between the two closest rays reaching the observation position so as to be not more than the diameter of the pupil of the observer.
The control means keeps the distance between the two closest rays reaching the observation position, not more than 2 mm.